The present invention relates to IR transceiver circuits. More specifically it relates to low cost transceiver circuits which are suitable for use in toys, such as toy guns, toy robots, cars, targets, helmets and similar items. Typically a pair of such toys are similarly equipped, as for example a pair of toy guns, so that one user can "shoot" at another user. The first person to shoot will send a modulated IR signal to the receiver of the other toy gun. The signal will be detected and an indication made that the first person has scored a hit. Other applications of such a circuit include the remote control of toy devices, such as robots, toy cars, or even devices such as televisions, radios or other equipment.
Infrared transmitters and receivers are known in the art as, for example, the well known infrared transmitter/receiver combinations employed in television receivers. Such circuits perform reliably under controlled conditions inside a home. When intended for use in toys, however, it is desirable that the transceiver circuits operate outdoors as well as in the home. Under these circumstnces, most existing transceiver circuits do not operate reliably due to ambient infrared radiation. Such radiation, principally due to sunlight, is unmodulated. Typically, the IR detectors of the receivers become saturated by the ambient IR, severely reducing the sensitivity of the circuit to modulated IR signals.
It is accordingly an object of the present invention to provide an improved transceiver circuit for toy guns and the like which is capable of operating under more severe conditions than conventional circuitry.
It is a further object of the invention to provide a low cost, reliable IR transceiver circuit for use in toys and related electronic equipment.
Another object of the invention is to provide a filter circuit for an IR receiver whereby good sensitivity to a modulated signal can be maintained even in the presence of ambient, unmodulated IR interference.
Other objects and advantages of the invention will be apparent from the remaining portion of the specification.